I was thinking of doing a big water change. I changed out 3 gallons yesterday and the test results didn't change much. Of course thats only a little over 10% water change so I'm not suprised. I have enough salt water to do another 5 gallons worth of a water change. Will that be enough to cause any change in the water test results? So far the tank is sitting at 8.2 as the pH, 0 ammonia, .25 nitrite and 20 nitrate. Those were my test results. I had a different guy at the LFS test my water and he said my pH was good at 8.2, 0 ammonia, 0 nitrite, and 20 nitrate, so either my nitrites are off or his are, but thats what will decide if the tank is cycled or not. He says the tank is cycled and the tank has been running for over 3 weeks now. We are having a major algae bloom and were advised to keep the amount of time the light is on to a minimum to get the algae to die off. When I asked if he thought the tank was cycled he said it was cycled. I then asked when he would advise putting corals or inverts in and he said give it a few more days to sit.

So what do you think? Should I do a 5g water change, re-test and see where I'm at? Trust the guy at the fish store?

Well it will all have to be tomorrow but I can do some in the morning, some at night. I also might add that they are using different methods of testing than I am. I don't know which method is for which test but I do know they use a dip-stick for one test, a wand with a meter for another, and I can't remember the others but I use the API Salt Water Master Test kit, so my results will be different from theirs depending on how I interpret the colors.

I'd like to add that you are understocked with live rock. If you plan on having a lesser bio-load then you're fine, but if you are stocking suitable inmates for a 20g I'd suggest buying more LR. Since you would be adding a significant amount, this would cause another mini-cycle, delaying the tank's readiness.

I'd go with your own results, LFS will tell you it is ready so you will begin buying product. Trust your instincts over another's potential deception. Progressive water changes are the best option, nitrates are tricky, mine hovered at 10ppm for ages before finally dropping to 0.

I'll be going to the LFS tomorrow to pick up another lb or two of LR. I have 11lbs right now and plan on having 20-25lbs in the tank. Thanks everyone for your suggestions and advice. I'm going to do a water change in just a moment.